Embodiments of the present disclosure relate generally to a gas turbine engine, and more particularly to a system and method for improving efficiency of the gas turbine engine.
Typically, gas turbine engines are used for converting thermal or heat energy into mechanical energy, which may then be used for applications, such as power generation, marine propulsion, and gas compression. In general, a gas turbine engine includes a compressor for compressing air and a combustor for combining the compressed air with fuel to form a fuel mixture. Thereafter, the fuel mixture is combusted or ignited in the combustor to generate a post combustion gas or a working gas. Typically, the post combustion gas is a high pressure, high temperature gas stream that is expanded while being conveyed through a turbine to convert thermal energy of the post combustion gas into mechanical energy. Further, in one example, the converted mechanical energy may be used to rotate a turbine shaft that is coupled to machinery, such as an electrical generator for producing electrical energy.
In general, during the process of combustion, the oxygen content in the compressed air may not be fully consumed. As a result, the post combustion gas that exits from the turbine includes at least 15% mass of oxygen, which has the potential of oxidizing more fuel. Therefore, some gas turbine engines deploy a reheat combustor, where the post combustion gas is re-combusted after being mixed with additional fuel. Further, the re-combusted post combustion gas is expanded in another turbine section to generate additional power. Thus, the deployment of the reheat combustor and another turbine section utilizes the oxidizing potential of the post combustion gas, which in turn increases the performance of the engine.
However, in conventional gas turbine engines, the reheat combustor poses significant challenges due to high temperature of the post combustion gas, reduced oxygen concentration in the post combustion gas, and presence of one or more species in the post combustion gas. This in turn poses substantial limitations on the combustor operation due to issues related to auto-ignition, flame stabilization, and emissions in the reheat combustor.